Tell us what your own answers are, so we can be sure we're not just doing your homework for you.

Unless stated otherwise, I do not care whether a statement, by itself, constitutes a persuasive political argument. I care whether it's true.---If this post has math that doesn't work for you, use TeX the World for Firefox or Chrome

Look into any studies that have to separate nature from nurture - this isn't really a psychology question, it's one of a scientific method used for things ranging from mental issues to things like juvenile diabetes.

'Look, sir, I know Angua. She's not the useless type. She doesn't stand there and scream helplessly. She makes other people do that.'

I think I found the answer. IQ is highly heritable so it's genes, however it is also Environment; children learn and score higher in school, if they are raised in a stable well educated environment. Also, they can test the theory if they study the performance of children who are adopted into a family than compare them to their biological parents. Also, they could study the differences between the biological children and the adoptive children in the same environment. Also, they can study the difference between Twins raised apart in different environments.

"What I thought I'd do was, I thought I'd pretend to be one of those deaf mutes"-J.D. Salinger

That confounds the environment of the "womb" with genetics, by the way.

In addition, twin studies have a problem in that twins are not like other children. Twins tend to have a number of problems more often than non-twins (various cognitive problems are more common).

As an example of how this could easily confound a twin study, suppose everyone has 100 IQ, except for people with a particular condition. 5% of the general population has this condition, as well as 10% of twins. If one twin has it, both twins have it. It is caused by insufficient resources during fetal development. The effect of this condition is that it drops your IQ to 80.

Despite genetics having zero impact on IQ in this model, you'll find a strong correlation between twin IQ raised apart.

One of the painful things about our time is that those who feel certainty are stupid, and those with any imagination and understanding are filled with doubt and indecision - BR